Addition polymerizable polyethers having pendant ethylenically unsaturated urethane groups

ABSTRACT

Addition polymerizable polyethers having pendant ethylenically unsaturated urethane groups are usefully employed as flooring materials and in other applications utilizing radiation curable or chemically curable materials. Such urethane polyethers are advantageously prepared by reacting a polyether polyol such as a hydroxy terminated polypropylene glycol with an isocyanatoalkyl ester of an ethylenically unsaturated acid such as 2-isocyanatoethyl methacrylate.

BACKGROUND OF THE INVENTION

This invention relates to polyethers having pendant ethylenicallyunsaturated groups that undergo addition polymerization upon exposure tosuitably active radiation and/or chemical initiation.

The use of organic polymers in coating compositions for application on awide variety of substrates such as floor materials, appliance housings,paper products, etc., is well known. Characteristically, such polymersare often either thermoplastic or thermosettable. For many coatingapplications, the thermoplastic polymers do not exhibit the necessaryresistance to abrasion and organic solvents. Unfortunately, the heatcurable, thermosettable polymers are usefully applied only to substratesthat can tolerate the temperatures often required to cure such polymers.In addition, thermal curing processes are often too time consuming to beeconomical in many applications.

Thus, it has been desirable to develop polymers which cure bynon-thermal means such as by moisture cure or radiation cure techniques.Moisture curable polymers are often unsatisfactory because of therestrictions of temperature and relative humidity necessary to achieve acrosslinked coating. Also, the time period required to achieve completecure (two to three weeks) is often impractical.

Polymers, which upon exposure to light or comparable radiation sourcecrosslink to form insoluble materials, exhibit the most desirableproperties in that they generally are cured rapidly and can be appliedto heat sensitive substrates. Accordingly, such radiation curablepolymers are often useful in coating applications as varnishes and inksas well as finish coats on flooring and other items such as countertops. Such applications usually require that the resulting insoluble,crosslinked coating by non-yellowing, abrasion resistant and stainresistant.

Unfortunately, many of the conventional radiation curable polymers, suchas epoxy acrylates, now being employed in conventional, UV curablevarnish and ink formulations are particularly sensitive to light,especially sunlight, in that they yellow and craze after relativelybrief periods of exposure. Other conventional radiation curablecompositions contain very toxic substances such as monomeric orunreacted isocyanate, hydroxyalkyl esters of acrylic acid and the like.Examples of conventional radiation curable and photo curable polymericmaterials are described in U.S. Pat. Nos. 3,928,299 and 3,924,033.

In view of the aforementioned deficiencies of conventional radiationcurable polymeric compositions, it is highly desirable to provide arelatively nontoxic substance which crosslinks readily and quickly uponexposure to low doses of relatively low energy radiation and/or chemicalinitiation to form a crosslinked coating exhibiting long-term toughness,abrasion resistance and stain resistance.

SUMMARY OF THE INVENTION

In one aspect the present invention is an addition polymerizablepolyether comprising a polyether backbone having at least one pendantethylenically unsaturated aliphatic urethane group which reacts uponexposure to (1) suitably active radiation, hereinafter called actinicradiation, and/or (2) chemical initiation. The polyether backbone isadvantageously poly(hydrocarbyleneoxy) wherein the hydrocarbylene is adivalent hydrocarbon moiety having at least 2 carbons, preferablyalkylene having at least 2 carbons. The ethylenically unsaturatedurethane group is more specifically characterized as an oxycarbonylaminoaliphatic ester of α,β-ethylenically unsaturated carboxylic acid whereinoxycarbonylamino is a moiety represented by the formula: ##STR1##Hereinafter, this addition polyether having at least one pendantethylenically unsaturated aliphatic urethane group shall be referred toas a urethane polyether.

In another aspect, the present invention is a method for coatingsubstrates such as floors, wood panels, paper, plastic sheets or sheetmetal with a coating composition comprising the aforementioned polymer(hereinafter called urethane polyether) and subsequently crosslinkingsaid polymer, by exposure to radiation, or chemical initiation, to forma relatively hard, tough, abrasion and chemical resistant coating whichadheres to the substrate.

In yet another aspect, the present invention is an additionpolymerizable composition comprising the aforementioned urethanepolyether and at least one addition polymerizable monomer which iscopolymerizable therewith.

In addition to the advantageous use of the urethane polyether in coatingapplications, such polymers are also useful in ink and varnishformulations and in other conventional compositions requiring aradiation curable polymer. These urethane polyethers are also useful incompositions employing other means of free radical polymerization suchas chemical free-radical generators, e.g., peroxygen and azo compounds.In such compositions, these addition polymerizable urethane polyethersmay be copolymerized with other addition polymerizable monomers such asstyrene, acrylonitrile, butadiene, ethyl acrylate and the like. Thesecompositions and the resulting copolymers are useful in the manufactureof foams, elastomers, moldings and the like.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The radiation curable urethane polyethers of this invention arepreferably those represented by the formula:

    Y[(R'"O--.sub.m R'"-Z].sub.x

wherein Y is hydroxyl, oxyhydrocarbyl, oxycarbonyl hydrocarbyl, anoxycarbonylamino aliphatic hydrocarbyl ester of an α,β-ethylenicallyunsaturated carboxylic acid or a residue of an active hydrogen initiatorsuitably employed in preparation of a polyether; each Z is individuallyhydroxyl oxyhydrocarbyl, oxycarbonyl hydrocarbyl or saidoxycarbonylamino aliphatic hydrocarbyl ester group provided that thepolyether contain at least one of said oxycarbonylamino ester groups,R'" is alkylene or haloalkylene; m is a whole number such that--R'"O)_(m) -R'"- has a number average molecular weight (M_(n)) fromabout 100 to about 100,000, especially from about 250 to about 10,000;and X is a whole number from 1 to 8, especially from 2 to 3. For thepurposes of this invention, hydrocarbyl is a monovalent hydrocarbonmoiety such as aryl, alkyl, alkenyl and the like.

The more preferred urethane polyethers of the present invention havepolyalkyleneoxy backbones bearing at least one pendant ethylenicallyunsaturated urethane group represented by the formula: ##STR2## whereineach R is independently hydrogen, alkyl or comparable inert substituent;R' is hydrogen, lower alkyl (C₁ -C₄) or ##STR3## R" is an inert groupsuch as alkoxy or polyalkylenoxy and m is a whole number preferably 1 to6, more preferably 2 to 4, and most preferably 2.

The urethane polyethers of the present invention are most advantageouslyprepared by first polymerizing in a known manner a diol such as ethyleneglycol, propylene glycol or butylene glycol; comparable epoxy compoundssuch as ethylene oxide, propylene oxide, epichlorohydrin orepibromohydrin; or polyol other than a diol. Such polymerizations arenormally carried out in the presence of an active hydrogen initiator anda Friedel-Crafts catalyst by charging the reactants to a closed vesseland heating them until polymerization is complete. Alternatively, thepolyether may be prepared using a conventional base catalyzed process.Suitable polyether polyols and methods for preparing them are describedin the following references which are incorporated herein by reference:U.S. Pat. Nos. 2,891,073; 3,058,921; 2,871,219 and British Pat. No.898,306.

The resulting polyether polyol is recovered in a conventional manner andreacted with an isocyanatoalkyl ester of an α,β-ethylenicallyunsaturated carboxylic acid under conditions sufficient to cause theisocyanato group to react with a hydroxy group of the polyether polyolto form a urethane linkage. Advantageously, this reaction is carried outin the presence of a urethane catalyst such as amine or anorganometallic catalyst, preferably an organometallic catalyst such asstannous octoate or dibutyltin dilaurate. The conditions employed incarrying out the urethane reaction involve maintaining the reactionmixture of the polyether polyol and isocyanatoalkyl ester, preferablyneat, or alternatively dissolved in a non-reactive solvent such as ethylacetate, toluene or cellosolve acetate at a temperature from ambient to140° C. in a vessel for a reaction time from about 1 to about 24 hours.The amounts of the isocyanatoalkyl ester can be stoichiometric orslightly in excess of the pendant hydroxy groups of the polyetherpolyol. However, the amount of ester is suitably less thanstoichiometric amounts, particularly if only partial capping of thepolyol is desired. The resulting polyether having pendant ethylenicallyunsaturated urethane groups is generally used without furtherpurification. If a solvent has been used in the reaction, it can beremoved, or the composition containing the solvent can be employed asis.

Exemplary isocyanatoalkyl esters used to prepare the desired polyetherinclude 2-isocyanatoethyl methacrylate, 2-isocyanoethyl acrylate,3-isocyanatopropyl methacrylate, 1-methyl-2-isocyanatoethyl methacrylateand 1,1-dimethyl-2-isocyanatoethyl acrylate with 2-isocyanatoethylmethacrylate being preferred. Suitable methods of preparing saidisocyanato esters are well known, e.g., as shown in U.S. Pat. Nos.2,718,516 and 2,821,544 and British Pat. No. 1,252,099.

The urethane polyether is generally a resinous (solid or semisolid) orviscous liquid material which varies in number average molecular weight(M_(n)) from about 250 to about 100,000, preferably from about 400 toabout 10,000, depending on the M_(n) of the polyether polyol used as astarting material. For purposes of this invention, M_(n) (number averagemolecular weight) is determined by measuring percent hydroxyl or thestarting polyol.

In preparing a photocurable coating formulation in accordance with thepresent invention, the aforementioned polyether having pendantethylenically unsaturated urethane groups is combined with an initiatoreffective to initiate crosslinking of the polymer on exposure toradiation, hereinafter referred to as a photointiator. For this purpose,the photoinitiator is advantageously dithiocarbamates, dithiocarbonates,thiuram compounds, thiazoles and xanthates, as well asα-phenylacetophenone derivatives such as benzil, benzoin and the benzoinethers, e.g., benzoin-methyl, -ethyl, -n-propyl and -isopropyl ethers.While the amount and type of photoinitiator employed will vary with theintensity and dosage of radiant energy to be employed, theaforementioned photoinitiators are usually employed in amounts fromabout 0.5 to about 8, preferably from about 1 to about 3, weight percentbased on the weight of the coating formulation. Of the foregoinginitiators, the benzoin ethers are preferred.

In preparing chemically initiated polymer products using the urethanepolyether of the present invention, conventional free radical generatingcompounds are employed to initiate addition polymerization of theurethane polyether or to initiate copolymerization of the urethanepolyether with one or more other ethylenically unsaturatedcopolymerizable monomers. Exemplary free radical generating compoundswhich are suitable for this purpose include peroxygen compounds, e.g.,peroxides, persulfates, percarbonates, and perborates, as well as azocompounds. Typically, such chemical initiators are employed in amountseffective to cause polymerization, e.g., from about 0.1% to about 10%based on the weight of polymerizable material, e.g., urethane polyetherand other monomer(s).

A nonreactive solvent and/or copolymerizable monomer is often employedin the coating formulation in order to reduce viscosity of theformulation and/or to impart additional properties to the resultingcrosslinked coating or article. Examples of suitable non-reactivesolvents for the urethane polyether include volatile, relatively lowviscosity liquid solvents such as aromatic hydrocarbons, e.g., benzeneand toluene; esters, e.g., ethyl acetate and cellosolve acetate;chlorinated solvents such as perchloroethylene and1,1,1-trichloroethane; and ethers such as dioxane, tetrahydrofuran aswell as dimethoxydiethylene and other glymes. When used, thenon-reactive solvents are normally employed in amounts sufficient toreduce the viscosity of the curable composition, usually from about 5 toabout 80, preferably from about 5 to about 30, weight percent based onthe combined weight of total curable composition and the solvent.Suitable copolymerizable monomers are monoethylenically andpolyethylenically unsaturated monomers which undergo additionpolymerization upon exposure to actinic radiation and/or chemicalinitiation. Examples of suitable monomers for this purpose includemonovinylidene aromatics, e.g., styrene, t-butylstyrene andar-chlorostyrene; polyvinyl aromatics such as divinyl benzene;unsaturated nitriles such as acrylonitrile; conjugated aliphatic dienes,e.g., butadiene; alkyl esters of α,β-ethylenically unsaturatedcarboxylic acids, e.g., ethyl acrylate, butyl acrylate and methylmethacrylate; vinyl esters such as vinyl acetate; di- and triesters ofα,β-ethylenically unsaturated carboxylic acid such as trimethylolpropane triacrylate and hexanediol diacrylate and the like, includingmixtures thereof.

When used, the copolymerizable monomers are normally employed in amountsin the range from about 0 to about 99.98 weight percent based on thetotal weight of the curable composition, i.e., combined weight of thecopolymerizable monomer and urethane polyether. In preparing a radiationcurable formulation, the amount of copolymerizable monomer normallyemployed is in the range of from 0 to about 50 weight percent based onthe total weight of the curable composition. In preparing a polymerpolyol which can be used as a starting ingredient in the production of apolyurethane molding or a polyurethane foam, the copolymerizablemonomer(s) is normally used in amounts in the range of from about 0 toabout 99.9, preferably from about 2 to about 70, most preferably fromabout 5 to about 50, weight percent based on the combined weight of theurethane polyether and the copolymerizable monomer(s). For purposes ofthis invention, a polymer polyol is a solution or dispersion of anypolymer in a polyether polyol.

In addition to the foregoing photoinitiators, nonreactive solvents andcopolymerizable monomers, other additives such as impact modifiers(rubber polymers and elastomers), pigments and fillers, stabilizers,fire retardants, etc., can be employed.

The aforementioned coating formulations are readily cast, sprayed orotherwise applied as films or coatings by conventional coatingtechniques used by those skilled in the art. Typically, the thickness ofthe film or coating will vary from about 0.0025 to about 0.125 mm, withthicknesses in the range from about 0.010 to about 0.055 mm beingpreferred.

When radiation curing is to be employed, the coating or film is thenexposed to sufficient actinic radiation to cure the coating or film to amaterial that is insoluble in aqueous or organic liquid media. Forpurposes of this invention, actinic radiation is any radiation whichwill cause the desired crosslinking reaction. Preferably, when theradiation curable composition contains methacrylate moieties, theradiation curing step is carried out in atmosphere that is substantiallyfree of oxygen. In order to achieve such a substantially oxygen-freeatmosphere, it is sufficient to overlay a thin film of a material whichtransmits the radiation such as clear plastic on the coating or film tobe cured. Other means may be used such as curing the coating or film ina chamber containing an essentially oxygen-free atmosphere such asnitrogen, helium or argon or by curing the coating or film under vacuum.Curable compositions, which contain acrylic instead of methacrylicmoieties, need not be irradiated in an oxygen-free environment in allinstances.

Examples of actinic radiation advantageously employed includeultraviolet light; accelerated particulate (ionizing) radiation whereinparticulates include electrons, protons, neutrons, etc.; X-rays; and thelike, with ultraviolet light being preferred. In the case of ultravioletlight radiation, suitable intensity is supplied by mercury vapor lamps.

The following examples are given as illustrative embodiments of theinvention and should not be construed as limiting its scope. In theseexamples, all parts and percentages are by weight unless otherwiseindicated.

EXAMPLE 1 Preparation of Urethane Polyether

Into a 250 ml round bottom flask fitted with an air-driven stirrer, awater condenser capped with a drying tube, an addition funnel and athermocouple controlled heating lamp are placed 51.43 g (0.0509 mole) ofa polypropylene glycol having a number average molecular weight, asdetermined by percent hydroxyl analysis, of 1010, and 2 drops ofstannous octoate as catalyst. The contents of the flask are heated to50° C. and 15.79 g (0.1018 mole) of 2-isocyanatoethyl methacrylate (IEM)is added dropwise over a period of 42 minutes with stirring. Heating ofthe stirred reaction mixture at approximately 50° C. is continued for aperiod of 1.4 hours and then the reaction mixture is allowed to cool toroom temperature for an additional 2 hours. Analysis of the resultingreaction product by an infrared spectrometer indicates no unreactedisocyanate remains in the reaction mixture. At room temperature, theproduct is a clear thick liquid which develops white crystals onstanding. Upon formulating 50 parts of this liquid with 50 parts oftrimethylolpropane triacrylate and exposing a thin layer of theresulting formulation to ultraviolet light, the layer cures to arelatively hard coating which is insoluble in water or hydrocarbonsolvents.

EXAMPLES 2-7 Preparation of Urethane Polyether

Following the procedure of Example 1, a 51.6-g portion (0.129 mole) of apolypropylene glycol having a molecular weight of 400 and 3 drops ofstannous octoate solution are heated with stirring to 50° C. A 40-gportion (0.258 mole) of IEM is added dropwise over a period of 1.5 hoursduring which an exotherm to 66° C. is observed. Infrared analysis of theresulting product indicates a complete reaction of the IEM.

Coating Formulation

A formulation consisting of 80 parts of the aforementioned urethanepolyether and 20 parts of trimethylolpropane triacrylate is combinedwith 3 parts of benzoin ether photoinitiator and 0.5 part ofmethyldiethanolamine. This formulation is cast as a layer onto aphosphate-treated steel substrate and cured to a ˜0.03 mm film byrepeatedly (five times) passing the coated substrate at the rate of˜30.5 meters per minute under a light source having three 100 wattmedium pressure mercury lamps. The resulting coating is tested forimpact strength and chemical resistance and the results are reported inthe following Table I.

Following the foregoing procedure, several additional compositions(Example Nos. 3-7) employing different urethane polyethers and differentreactive diluents are prepared and formed into coatings which are thentested by the procedures described herein, the results of these testsare reported in the following Table I.

                                      TABLE I                                     __________________________________________________________________________                     Copolymeriz-                                                                  able Monomer                                                 Ex- Isocyanate Ester/Polyol(1)                                                                 (2)       Benzoin Ether           Solvent Tough-             ample      Mole       Amount                                                                             Photoinitiator                                                                        Radiation   Hard-                                                                             Resist- ness               No. Type   Ratio Type pph  pph(3)  Conditions(5)                                                                             ness                                                                              ance    in-lb(8)           __________________________________________________________________________    2   IEM/PPG                                                                              2:1   TMPTA                                                                              20   3(4)    3 × 100w(30.5 MPM)                                                                  HB  >100                                                                                   4K                    (400)                          5 passes                                   3   IEM/GPPG                                                                             3:1   PEA  20   3(4)    3 × 100w                                                                            4H  >100                                                                                  <4                     (260)                          1 pass                                     4   IEM/SP 7:1   PEA  40   3(4)                                                   (1061)                     1:1 1 × 200w(30.5 MPM)                                                  wt  5 passes    2B    73                                                                                  70K                    IEM/PO-EO                                                                            3:1   PEA  50   3  3 ratio                                             (4700)                                                                    5   IEM/PO-EO                                                                            3:1                                                                    (4700)     1:1                 3 × 100w(30.5 MPM)                                  wt                                                                              TMPTA                                                                              20   3       3 passes    3H  >100                                                                                  10K                    IEM/GPPG                                                                             3:1 ratio                                                              (260)                                                                     6   50 IEM/PO-EO                                                                         3:1                                                                    (4700)     1:1                 3 × 100w(30.5 MPM)                                  wt                                                                              TMPTA                                                                              20   3       3 passes    2H  >100                                                                                  40K                    50 IEM/PPG                                                                           2:1 ratio                                                              (400)                                                                     7   IEM/GPPG                                                                             1:0.67                                                                              None --   3       3 × 100w(30.5 MPM)                                                                  2H  >100                                                                                  12K                    (260)                          1 pass                                     __________________________________________________________________________     (1)                                                                           IEM  2isocyanatoethyl methacrylate                                            PPG (1010)  polypropylene glycol (M.sub.n1010)                                PPG (400)  polypropylene glycol (M.sub.n400)                                  GPPG (260)  glycerine initiated polypropylene glycol (M.sub.n260)             SP (1061)  sorbitol initiated polyol having 7 hydroxyl groups                 (M.sub.n1061)                                                                 POEO (4700)  glycerine initiated polyalkylene glycol made from propylene      oxide and ethylene oxide (M.sub.n4700)                                        In Example No. 4, the two specified compositions of Isocyanate                Ester/Polyol, copolymerizable monomer and benzoin ether initiator are         combined in a 1:1 weight ratio.                                               In Example Nos. 5 and 6, the two specified Isocyanate Ester/Polyols are       combined in a 1:1 weight ratio.                                               (2) TMPTA  trimethylolpropane triacrylate                                     PEA  phenoxyethyl acrylate                                                    pph  parts of initiator per hundred parts of urethane polyether plus          copolymerizable monomer                                                       (3) parts of benzoin ether photoinitiator per hundred parts of urethane       polyether plus copolymerizable monomer                                        (4) photoinitiator also contains 0.5 part of methyldiethanol amine per        hundred parts of urethane polyether plus copolymerizable monomer              (5) Radiation conditions indicated by light source (e.g., 3 × 100w      3 lamps at 100 watts each), rate of sample travel under light source in       meters/minute (MPM) and number of passes under the light source               (6) Coatings are covered with polyethylene terephthalate film during          irradiation. Hardness measured by the pencil hardness test, the rating        being the hardest pencil that does not scratch the coating surface.           (7) Solvent resistance measured by double rubs with a cotton swab soaked      with methyl ethyl ketone.                                                     (8) Toughness measured by a Gardner impact tester with the rating being       the greatest number of inches a 1 lb weight can be dropped onto the           reverse side of a coated panel (0.635 mm) without rupturing the coating. 

Film Testing

Using the cured coatings of Examples Nos. 5 and 6 of the aforementionedTable I, the coatings are tested for resistance to abrasion,discoloration and staining. The results of these tests are reported inTable II.

                                      TABLE II                                    __________________________________________________________________________                       Abrasion                                                   Example                                                                            Yellow Resistance(1)                                                                        Resistance                                                                             Stain Resistance(3)                               No.  Initial YI                                                                         YI 500 Hrs                                                                          ΔYI                                                                        mg/100 Cycles(2)                                                                       Mustard                                                                            Lipstick                                                                           Ink                                     __________________________________________________________________________    5    15.088                                                                             21.327                                                                              6.239                                                                            1.1      Slight                                                                             None Very                                                                          Faint                                   6    15.742                                                                             18.201                                                                              2.459                                                                            2.6      "    "    Slight                                  __________________________________________________________________________     (1) ASTM D1925-66T wherein coatings are applied to Morest paper and cured     using 5 passes under 3 × 100 watt lamps at 100 feet per minute.         Morest paper, blank, has an initial YI (yellow index) of 10.072 and YI of     16.486 after 500 hours. Increase in yellow is indicated by ΔYI. An      uncoated (blank) Morest paper exhibits a ΔYI of 6.414.                  (2) Tabor Abrasion   determined by measuring weight loss of coating after     100 cycles with CS17 wheel and a 1000 g weight. A coating exhibiting a        weight loss of less than 2 mg under such conditions has superior abrasion     resistance. A loss of less than 15 mg/100 cycles indicates acceptable         abrasion resistance.                                                          (3) The staining agent is applied to the coating, allowed to remain for 5     minutes and then wiped off with tissue paper soaked with ethanol.        

EXAMPLE 8

Eighty parts of the blend of radiation curable urethane polyethers ofExample 6 is combined with 20 parts of styrene and 3 weight parts ofbenzoin ether photoinitiator. A coating of the resulting formulation iscast onto phosphate treated steel panels. The coated panel is coveredwith poly(ethylene terephthalate) film and passed under three 100 wattmedium pressure mercury vapor lamps (15 passes at a rate of 30.5 MPM).The resulting cured coating (thickness ˜0.017 mm) has the followingproperties.

Hardness(6): B

Solvent Resistance(7): 26 MEK

Toughness(8): >140 in-lbs

Tape Adhesion(9): >95%

wherein (6) through (8) are the same as in Table I and (9) is acrosshatch adhesion test wherein the coating scored with a sharpinstrument into 100 squares/square inch and then adhered to a pressuresensitive, glass reinforced adhesive tape. The tape is pulled quicklyfrom the crosshatched section. Adhesion is determined by percent ofsquares remaining on the panel.

EXAMPLE 9

In the preparation of the urethane polyether of Example 7, 50 g (0.588equivalent) of glycerine initiated polypropylene glycol (M_(n) -260) iscombined with 0.0191 g of hydroquinone and 2 drops of stannous octoatecatalyst and heated to 50° C. To these ingredients a 45.64 g-portion(0.294 equivalent) is added with stirring over a period of 1.7 hourswith an exotherm to 59° C. being observed. The resulting polyether hasboth pendant vinyl and hydroxyl moiety in mole ratio of ˜1:1.

A 22.17 g-portion (0.068 equivalent of ethylenic unsaturation, 0.068equivalent of hydroxyl) of this polymer is combined with 43.42 g (0.417equivalent of ethylenic unsaturation) of styrene and 41.5 g (0.488equivalent of hydroxyl) of the polypropylene glycol (M_(n) -260) bymixing such that entrapment of air into the mixture is avoided. To thismixture is added with stirring 81.92 g (0.583 equivalent of NCO) of aprepolymer of toluene diisocyanate and the polypropylene glycol (M_(n)-260) and 0.8 cc of t-butyl perbenzoate catalyst. To the resultingmixture is added 0.5 cc of lead octoate solution (24 percent active) andrapidly mixed into the mixture. The resulting formulation is immediatelypoured into a 30.5 cm×30.5 cm×0.3 cm aluminum mold. After a few minutes,the molding is removed from the mold and maintained at 60° C. for onehour.

The cured molding is flexible and exhibits more dimensional stabilityand fewer surface deformities (bumps) than do moldings prepared fromconventional instant set polyurethane formulations which employ onlystyrene as the copolymerizable monomer.

EXAMPLE 10

A radiation curable formulation is prepared by blending 10 g of theurethane polyether of Example 4 with 0.3 g of benzoin etherphotoinitiator. This formulation is cast as a film onto a steelsubstrate and cured by repeatedly (four times) passing the coatedsubstrate at the rate of ˜30.5 meters per minute under a light sourcehaving three 100-watt medium pressure mercury lamps. The cured coatingis soft, but not tacky to touch, and exhibits moderate resistance toorganic solvent such as methyl ethyl ketone.

EXAMPLE 11

A 400-g portion (0.0825 mole) of PO-EO (4700) polyglycol as described inTable I is charged into a one liter, 3-necked round bottom flaskequipped with an addition funnel, stirrer, condenser, thermocouple andnitrogen sparge. The polyglycol is heated with stirring to 50° C. and1.112 g (0.0072 mole) of IEM in 50 g of methylene chloride is added tothe flask. The resulting mixture is heated to 120° C. at which time 100g of styrene containing 0.7 g of azobisisobutyronitrile are added withstirring to the mixture over a period of 30 minutes. After an additional40 minutes, 0.7 g of azobisisobutyronitrile in 15 g of methylenechloride is added to the reaction mixture over a period of 20 minutes.The reaction is allowed to continue for an additional two hours afterwhich time the reaction product is placed under vacuum for 45 minutes.The resulting polymer polyol is a stable dispersion of polystyrene inpolyglycol having a Brookfield viscosity (Model RV) of 2912 cps at 18°C. using a #4 spindle operating at 50 rpm.

For purposes of comparison, preparation of a polymer polyol is attemptedby following the foregoing procedure except that no IEM is employed. Thereaction is stopped after the reaction mixture becomes so viscous thatthe stirrer is inoperable. The reaction product is not a stabledispersion and is extremely viscous. Thus, it is shown that the reactionproduct of the polyglycol and the IEM contributes significantly to theformation of a stable dispersion of polystyrene in the polyglycol.

When the stable polymer polyol dispersion of this example is employed asthe polymer polyol component in an otherwise conventional process forpreparing a high resiliency polyurethane foam, a foam having excellentphysical properties is obtained.

What is claimed is:
 1. An addition polymerizable polyether having apolyether backbone bearing at least one pendant group which is anoxycarbonylamino aliphatic ester of an α,β-ethylenically unsaturatedcarboxylic acid.
 2. The polyether of claim 1 which is represented by theformula:

    Y--(R'"O--.sub.m R'"-Z].sub.x

wherein Y is hydroxyl, an oxycarbonylamino ester of an α,β-ethylenicallyunsaturated carboxylic acid or a residue of an active hydrogen initiatorsuitably employed in preparation of a polyether; each Z is individuallyoxyhydrocarbyl, oxycarbonyl hydrocarbyl or said oxycarbonylamino estergroup provided that the polyether contains at least one of saidoxycarboxylamino ester groups, R'" is alkylene or haloalkylene whereinalkylene has at least two carbons; m is a whole number such that--R'"O)_(m) -R'"- has a number average molecular weight from about 100to about 100,000, and x is a whole number from 1 to
 8. 3. The polyetherof claim 2 wherein the oxycarbonylamino ester group is represented bythe formula: ##STR4## wherein each R is independently hydrogen, alkyl orcomparable inert substituent; R' is hydrogen, lower alkyl parable inertsubstituent; R' is hydrogen, lower alkyl (C₁ -C₄) or ##STR5## R" is aninert group such as alkoxy or polyalkylenoxy and m is a whole numberpreferably 1 to 6, more preferably 2 to 4, and most preferably
 2. 4. Thepolyether of claim 3 wherein the oxycarbonylamino ester group isrepresented by the formula: ##STR6##
 5. A urethane polyether which isthe reaction product of a polyether polyol and an isocyanatoalkyl esterof an α,β-ethylenically unsaturated carboxylic acid.
 6. The polyether ofclaim 5 wherein the polyether polyol is a polyethylene glycol or apolypropylene glycol and the isocyanatoalkyl ester is 2-isocyanatoethylmethacrylate.
 7. An addition polymerizable composition comprising theurethane polyether of claim 1 and an addition polymerizable monomerwhich is copolymerizable therewith.
 8. The composition of claim 7wherein the monomer is a monovinylidene aromatic, an ethylenicallyunsaturated nitrile, a conjugated diene or an ester of anα,β-ethylenically unsaturated carboxylic acid.
 9. The composition ofclaim 8 wherein the ester is trimethylol propane triacrylate orhexanediol diacrylate.